Capacitive Fill Level Sensor Segmented Electrode Drainage Pump

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Solution Overview

Problem

Drainage pump systems face challenges with high costs and reduced accuracy when level sensors are attached to the fluid collection container, especially with inhomogeneous liquids and small filling quantities, and existing sensors attached to the drainage pump unit are less accurate compared to container-side sensors.

Innovation Solution

A drainage pump unit with a capacitive fill level sensor featuring at least two electrodes, where one is segmented, arranged on the suction pump housing, allowing for accurate measurement by compensating for fluid properties and environmental effects, and enabling the use of the same sensor for different container shapes and sizes.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If level sensors are attached to the fluid collection container, then measurement precision is improved, but device complexity and cost increase

Engineering Contradiction:
Improvefill level measurement accuracyVSAvoidsensor attachment complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The housing wall acts as an intermediary medium between the sensor and the fluid. The capacitive sensor measures the fill level through the housing wall, eliminating the need for direct contact between the sensor and fluid while maintaining measurement accuracy. This resolves the contradiction by providing accurate measurements without requiring complex sensor attachment to the container.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Device complexity

If level sensors are attached to the drainage pump unit, then device complexity is reduced, but measurement precision deteriorates

Engineering Contradiction:
Improvesensor system simplicityVSAvoidfill level measurement accuracy
Core Design Contradiction:
Device complexityVSMeasurement precision

Solution Approach 1:

The patent replaces mechanical contact-based level sensing with capacitive field-based sensing. The capacitive sensor detects fill level through electromagnetic field interaction through the housing wall, eliminating mechanical complexity while maintaining or improving measurement precision compared to traditional contact sensors.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

3Device complexity

If traditional capacitive sensors are used with inhomogeneous liquids, then measurement precision deteriorates, but device complexity remains simple

Engineering Contradiction:
Improvesensor structure simplicityVSAvoidfill level measurement accuracy
Core Design Contradiction:
Device complexityVSMeasurement precision

Solution Approach 1:

The patent changes the measurement parameters by using capacitive coupling through the housing wall rather than direct fluid contact. This parameter change allows accurate measurement of inhomogeneous liquids because the measurement is taken through the wall where fluid homogeneity is less critical, maintaining simple sensor structure while improving precision.

Inventive Principle:
Principle #35Parameter changes

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

The solution reduces costs by minimizing container sensor requirements while maintaining high measurement accuracy, allowing for precise fill level detection, including intermediate heights and filling speed monitoring, and compensating for environmental influences.

Implementation Method 1

A capacitive fill level sensor (7) arranged on the suction pump housing (1) to detect a fill level in the fluid collection container (2)

Methodology Applied
Scientific EffectCapacitance: Capacitance

Data Source

PatentEP2665498B1Drainage pump unit
Publication Date: 2017.05.03 MEDELA HLDG AG
  • EP2665498B1 patent drawingFigure 1
  • EP2665498B1 patent drawingFigure 2
  • EP2665498B1 patent drawingFigure 3

AI summary

The invention relates to a drainage pump unit for suctioning body fluids by means of a suction pump, comprising a suction pump housing (1) and a suction pump arranged therein, wherein a fluid collecting container (2) can be detachably fastened to the suction pump housing (1) and wherein a capacitive filling level sensor (7) for detecting a filling level in the fluid collecting container (2) is arranged on the suction pump housing (1). The filling level sensor (7) comprises at least two electrodes (70, 71), which are mutually spaced and extend over a common distance. A first (70) of said electrodes is integral and a second (71) of said electrodes is segmented. Said arrangement enables inexpensive fluid collecting containers to be produced yet nevertheless ensures high measuring accuracy.